{"id":{"repo_id":"ucf","oai_identifier":"oai:stars.library.ucf.edu:etd-1087"},"canonical_url":"https://search.dev.ndltd.org/etd/ucf/oai:stars.library.ucf.edu:etd-1087","repository":{"repo_id":"ucf","name":"Central Florida","base_url":"https://stars.library.ucf.edu/do/oai/"},"display":{"title":"Comparison Of Square-hole And Round-hole Film Cooling: A Computational Study","abstract":"Film cooling is a method used to protect surfaces exposed to high-temperature flows such as those that exist in gas turbines. It involves the injection of secondary fluid (at a lower temperature than that of the main flow) that covers the surface to be protected. This injection is through holes that can have various shapes; simple shapes such as those with a straight circular (by drilling) or straight square (by EDM) cross-section are relatively easy and inexpensive to create. Immediately downstream of the exit of a film cooling hole, a so-called horseshoe vortex structure consisting of a pair of counter-rotating vortices is formed. This vortex formation has an effect on the distribution of film coolant over the surface being protected. The fluid dynamics of these vortices is dependent upon the shape of the film cooling holes, and therefore so is the film coolant coverage which determines the film cooling effectiveness distribution and also has an effect on the heat transfer coefficient distribution. Differences in horseshoe vortex structures and in resultant effectiveness distributions are shown for circular and square hole cases for blowing ratios of 0.33, 0.50, 0.67, 1.00, and 1.33. The film cooling effectiveness values obtained are compared with experimental and computational data of Yuen and Martinez-Botas (2003a) and Walters and Leylek (1997). It was found that in the main flow portion of the domain immediately downstream of the cooling hole exit, there is greater lateral separation between the vortices in the horseshoe vortex pair for the case of the square hole. This was found to result in the square hole providing greater centerline film cooling effectiveness immediately downstream of the hole and better lateral film coolant coverage far downstream of the hole.","abstract_html":"Film cooling is a method used to protect surfaces exposed to high-temperature flows such as those that exist in gas turbines. It involves the injection of secondary fluid (at a lower temperature than that of the main flow) that covers the surface to be protected. This injection is through holes that can have various shapes; simple shapes such as those with a straight circular (by drilling) or straight square (by EDM) cross-section are relatively easy and inexpensive to create. Immediately downstream of the exit of a film cooling hole, a so-called horseshoe vortex structure consisting of a pair of counter-rotating vortices is formed. This vortex formation has an effect on the distribution of film coolant over the surface being protected. The fluid dynamics of these vortices is dependent upon the shape of the film cooling holes, and therefore so is the film coolant coverage which determines the film cooling effectiveness distribution and also has an effect on the heat transfer coefficient distribution. Differences in horseshoe vortex structures and in resultant effectiveness distributions are shown for circular and square hole cases for blowing ratios of 0.33, 0.50, 0.67, 1.00, and 1.33. The film cooling effectiveness values obtained are compared with experimental and computational data of Yuen and Martinez-Botas (2003a) and Walters and Leylek (1997). It was found that in the main flow portion of the domain immediately downstream of the cooling hole exit, there is greater lateral separation between the vortices in the horseshoe vortex pair for the case of the square hole. This was found to result in the square hole providing greater centerline film cooling effectiveness immediately downstream of the hole and better lateral film coolant coverage far downstream of the hole.","abstract_has_math":false,"creators":["Durham, Michael Glenn"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Kapat, Jayanta S."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2004,"date_issued":"2004-01-01T08:00:00Z","date_published":"2004-01-01T08:00:00Z","updated_at":"2026-07-24T05:08:08Z","subjects":["Computational fluid dynamics","Film cooling","Gas turbines","Heat transfer","Turbomachinery","Engineering","Dissertations, Academic -- Engineering and Computer Science; Engineering and Computer Science -- Dissertations, Academic"],"languages":["English"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["CFE0000044"],"render_values":[{"text":"CFE0000044","href":null,"code":true}]}]},"links":{"outbound_url":"https://stars.library.ucf.edu/etd/88","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Kapat, Jayanta S."]},{"key":"dc:creator","label":"Author","values":["Durham, Michael Glenn"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["Masters Thesis (Open Access)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Computational fluid dynamics","Film cooling","Gas turbines","Heat transfer","Turbomachinery","Engineering","Dissertations, Academic -- Engineering and Computer Science; Engineering and Computer Science -- Dissertations, Academic"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["CFE0000044"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://stars.library.ucf.edu/etd/88"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["<p>If this is your thesis or dissertation, and want to learn how to access it or for more information about readership statistics, contact us at <a href=\"mailto:STARS@ucf.edu\">STARS@ucf.edu</a></p>","Master of Science (M.S.)","College of Engineering and Computer Science","Mechanical, Materials, and Aerospace Engineering","Mechanical, Materials and Aerospace Engineering"]},{"key":"dc:description.abstract","label":"Abstract","values":["Film cooling is a method used to protect surfaces exposed to high-temperature flows such as those that exist in gas turbines. It involves the injection of secondary fluid (at a lower temperature than that of the main flow) that covers the surface to be protected. This injection is through holes that can have various shapes; simple shapes such as those with a straight circular (by drilling) or straight square (by EDM) cross-section are relatively easy and inexpensive to create. Immediately downstream of the exit of a film cooling hole, a so-called horseshoe vortex structure consisting of a pair of counter-rotating vortices is formed. This vortex formation has an effect on the distribution of film coolant over the surface being protected. The fluid dynamics of these vortices is dependent upon the shape of the film cooling holes, and therefore so is the film coolant coverage which determines the film cooling effectiveness distribution and also has an effect on the heat transfer coefficient distribution. Differences in horseshoe vortex structures and in resultant effectiveness distributions are shown for circular and square hole cases for blowing ratios of 0.33, 0.50, 0.67, 1.00, and 1.33. The film cooling effectiveness values obtained are compared with experimental and computational data of Yuen and Martinez-Botas (2003a) and Walters and Leylek (1997). It was found that in the main flow portion of the domain immediately downstream of the cooling hole exit, there is greater lateral separation between the vortices in the horseshoe vortex pair for the case of the square hole. This was found to result in the square hole providing greater centerline film cooling effectiveness immediately downstream of the hole and better lateral film coolant coverage far downstream of the hole."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Comparison Of Square-hole And Round-hole Film Cooling: A Computational Study"]}]}],"canonical_facts":{"dc:contributor":["Kapat, Jayanta S."],"dc:creator":["Durham, Michael Glenn"],"dc:description":["<p>If this is your thesis or dissertation, and want to learn how to access it or for more information about readership statistics, contact us at <a href=\"mailto:STARS@ucf.edu\">STARS@ucf.edu</a></p>","Master of Science (M.S.)","College of Engineering and Computer Science","Mechanical, Materials, and Aerospace Engineering","Mechanical, Materials and Aerospace Engineering"],"dc:description.abstract":["Film cooling is a method used to protect surfaces exposed to high-temperature flows such as those that exist in gas turbines. It involves the injection of secondary fluid (at a lower temperature than that of the main flow) that covers the surface to be protected. This injection is through holes that can have various shapes; simple shapes such as those with a straight circular (by drilling) or straight square (by EDM) cross-section are relatively easy and inexpensive to create. Immediately downstream of the exit of a film cooling hole, a so-called horseshoe vortex structure consisting of a pair of counter-rotating vortices is formed. This vortex formation has an effect on the distribution of film coolant over the surface being protected. The fluid dynamics of these vortices is dependent upon the shape of the film cooling holes, and therefore so is the film coolant coverage which determines the film cooling effectiveness distribution and also has an effect on the heat transfer coefficient distribution. Differences in horseshoe vortex structures and in resultant effectiveness distributions are shown for circular and square hole cases for blowing ratios of 0.33, 0.50, 0.67, 1.00, and 1.33. The film cooling effectiveness values obtained are compared with experimental and computational data of Yuen and Martinez-Botas (2003a) and Walters and Leylek (1997). It was found that in the main flow portion of the domain immediately downstream of the cooling hole exit, there is greater lateral separation between the vortices in the horseshoe vortex pair for the case of the square hole. This was found to result in the square hole providing greater centerline film cooling effectiveness immediately downstream of the hole and better lateral film coolant coverage far downstream of the hole."],"dc:format":["application/pdf"],"dc:identifier":["CFE0000044"],"dc:identifier.uri":["https://stars.library.ucf.edu/etd/88"],"dc:language":["English"],"dc:subject":["Computational fluid dynamics","Film cooling","Gas turbines","Heat transfer","Turbomachinery","Engineering","Dissertations, Academic -- Engineering and Computer Science; Engineering and Computer Science -- Dissertations, Academic"],"dc:title":["Comparison Of Square-hole And Round-hole Film Cooling: A Computational Study"],"dc:type":["Masters Thesis (Open Access)"]},"updated_at":"2026-07-24T05:08:08Z"}